By The Big Buy desk · Last verified 12 October 2026
You probably need an air purifier if someone at home has asthma or allergies, or when the haze returns: HealthHub notes that portable purifiers can further reduce indoor particles once doors and windows are shut. You may need a dehumidifier if a room smells musty, grows mould or dries laundry slowly. Prices are modest: in mid-2026, one brand’s bedroom purifiers started from about S$180 and living-room models cost about S$450 to S$500 on promotion, with H13 filters replaced roughly every two years. Common 12-litre-a-day dehumidifiers have sold for about S$180 to S$410. Neither appliance carries a mandatory NEA energy label, so check the wattage yourself.
Clean, comfortable air makes a home feel lighter, especially in our humid climate. Here is how to tell whether you need either machine, and how to buy well.
Quick facts
- Look for a true HEPA filter (H13 is common) and the smoke CADR figure on purifiers.
- Rule of thumb for haze: clean the room’s air about four to five times an hour.
- Purifier filters: roughly every 24 months for one brand’s H13 filters; packs about S$30 to S$268.
- Dehumidifiers are rated by litres of water removed per day; 12 litres a day is a common home size.
- Air purifiers and dehumidifiers are not on NEA’s mandatory energy labelling list.
- During haze, close windows and doors when outdoor air worsens, then run the purifier.
Do you need one?
| Your situation | Air purifier | Dehumidifier |
|---|---|---|
| Haze season, especially with young children, elderly or pregnant family members | Yes, for the bedroom first | No |
| Asthma, dust or pet allergies | Helpful | Helpful if dust mites and mould are triggers |
| Musty wardrobe, mould spots, damp walls | No | Yes |
| Drying laundry indoors | No | Yes, speeds drying |
| Aircon running most of the day | Optional | Usually not; aircon already removes moisture |
What they cost
| Item | Example price | Suits |
|---|---|---|
| Small purifier (one brand, June 2026 promotion) | From S$180 | HDB bedroom or study, about 10 to 14 m² |
| Mid purifier, smoke CADR about 319m³/h | S$258 | Bedroom to small living room |
| Large purifier, smoke CADR about 488 to 580m³/h | S$458 to S$498 | Living rooms of about 30 to 50 m² |
| 12L-a-day dehumidifier (various brands) | About S$179 to S$409 | Bedrooms, store rooms |
| 2-in-1 purifier and dehumidifier | About S$458 to S$799 | Damp rooms needing both |
Purifier prices are from Novita’s e-store in June 2026, mostly on promotion; dehumidifier prices are from a SingSaver round-up of listed models. Prices move often, so compare on the day.
Sizing and running costs
- Measure the room in square metres.
- For a purifier, divide the smoke CADR (in cubic metres an hour) by 12 to estimate the floor area it can clean five times an hour with a 2.4m ceiling. A CADR of 320 covers roughly 27 m² at that rate; makers’ larger coverage claims usually assume fewer air changes.
- For a dehumidifier, pick a litres-per-day rating to match how damp the room is; bigger, damper rooms need more.
- Check wattage and noise on the spec sheet, especially for bedrooms.
- Budget for filters on purifiers, and remember to empty the dehumidifier tank or connect a drain hose.
Worked example: electricity
A purifier drawing 50W for 8 hours a day uses 12kWh a month. At 27 cents per kWh, the rate NEA uses on energy labels, that is about S$3.24 a month. A 200W dehumidifier on the same schedule uses 48kWh, about S$12.96 a month. Use the wattage on your model and the rate on your own bill for a precise figure.
The WahLiao Verdict
Buy an air purifier if you have allergy sufferers at home or want to be ready for haze: a HEPA model sized for the main bedroom is the best first purchase, and it costs a few dollars a month to run. Buy a dehumidifier only if you see damp, mould or slow-drying laundry; aircon-heavy homes rarely need one. Size both to the room, check the wattage, and budget for filters from the start.
Questions people ask
Will an air purifier protect us during haze?
It helps reduce indoor particles, as long as windows and doors are shut. Follow the PSI-based health advice for outdoor activity, especially for children, the elderly and those with heart or lung conditions.
Do ionisers or ozone generators work better?
A mechanical HEPA filter is the proven choice for particles. Avoid devices that deliberately produce ozone, which can irritate the lungs.
Is a 2-in-1 purifier and dehumidifier a good deal?
It saves space, but the purifier side usually has a lower CADR than a dedicated unit at the same price. Buy one only if you need both functions in the same room.
Can I use climate vouchers on these?
Climate vouchers cover a set list of energy- and water-efficient items. Check the current list before you buy; see our guide to energy labels and climate vouchers.
Sources: HealthHub, haze protection and PSI advice; NEA, appliances covered by mandatory energy labelling; The Money Bees, purifier prices, CADR and filters, June 2026; SingSaver, dehumidifier models and prices. The Big Buy explains; it does not advise.
Read next: Energy Labels and Climate Vouchers: What the Ticks Mean and How to Spend S$400 · Aircon Servicing and Replacement: What It Costs and How Often · Back to The Big Buy
For what’s worth it this week, with the bill shown, read The WahLiao Week.
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